Revert "Eliminate fake-Isolate workaround from concurrent sweeper."

runtime/vm/raw_object.cc

Index: runtime/vm/raw_object.cc
===================================================================
--- runtime/vm/raw_object.cc	(revision 44632)
+++ runtime/vm/raw_object.cc	(working copy)
@@ -65,11 +65,6 @@
 
 
 intptr_t RawObject::SizeFromClass() const {
-  return SizeFromClass(Isolate::Current()->class_table());
-}
-
-
-intptr_t RawObject::SizeFromClass(const ClassTable* class_table) const {
   // Only reasonable to be called on heap objects.
   ASSERT(IsHeapObject());
 
@@ -196,6 +191,9 @@
     }
     default: {
       // Get the (constant) instance size out of the class object.
+      // TODO(koda): Add Size(ClassTable*) interface to allow caching in loops.
+      Isolate* isolate = Isolate::Current();
+      ClassTable* class_table = isolate->class_table();
 #if defined(DEBUG)
       if (!class_table->IsValidIndex(class_id) ||
           !class_table->HasValidClassAt(class_id)) {